Spraying device

Abstract

The invention relates to a powder spraying device for a printing press, comprising a first spray bar (6) and a second spray bar (7), which are arranged one after the other in the transport direction (T) of the sheet. The second spray bar (7) has a row of spray heads (9). There are drive means (10) for moving the spray heads (9) into defined settings. In the defined settings, the spray heads (9) have different spacings (a, b) from one another in the row.

Description

Technical Field

[0001] The present invention relates to a powder spraying device for use in a printing press, comprising a first spray bar and a second spray bar, the first spray bar and the second spray bar being arranged sequentially back and forth along the conveying direction of the sheets. Background Technology

[0002] Such a spraying device is described in DE 10 2019 214 114 A1. Using this prior art device, a method can be implemented in which powder is applied uniformly across the width of the sheet by means of a first row of nozzles and simultaneously applied in a zoned manner across the width of the sheet by means of a second row of nozzles, wherein, per unit area, more powder is applied by means of the second row of nozzles than by means of the first row of nozzles. Summary of the Invention

[0003] The objective of this invention is to provide an additional apparatus capable of implementing methods disclosed in the prior art.

[0004] According to the present invention, the task is solved by a powder spraying device for a printing press, the spraying device comprising a first spray bar and a second spray bar arranged sequentially along the sheet conveying direction, characterized in that the second spray bar has a row of spray heads; there is a drive device for moving the spray heads to a predetermined setting; in the predetermined setting, the spray heads have different spacings relative to each other within the row.

[0005] Various expansions are possible:

[0006] The drive unit can be motorized (or electric).

[0007] Therefore, a motor can be installed on each spray head.

[0008] The total number of spray heads on the second spray bar can be less than the total number of spray heads on the first spray bar.

[0009] In the defined configuration, the spray head of the first spray bar can be aligned with the gap between the spray head of the second spray bar along the conveying direction. Attached Figure Description

[0010] Other structurally and functionally advantageous extensions of the invention will become apparent from the following description of the embodiments and accompanying drawings, in which:

[0011] Figure 1 A sheet printing press with a powder-sprinkling device is shown;

[0012] Figures 2 to 4The settings of the powder spraying device's spray bar for different printing jobs are shown;

[0013] Figure 5 Show Figure 4 A magnified local area;

[0014] Figure 6 The spray bar section with the drive unit is shown in a view viewed from below;

[0015] Figure 7 The spray bar section with the drive unit is shown in a view taken from the front. Detailed Implementation

[0016] Figure 1 An offset printing press 1 is shown, which has a paper receiver 2 and a printing mechanism 3. In the paper receiver 2, the printed sheets are conveyed along the conveying direction T and powder is sprayed on them by a spraying device 4. The sheets are then placed on a stack 5.

[0017] Figure 2 The diagram shows a spraying device 4 with a first spray bar 6 and a second spray bar 7, arranged sequentially along the conveying direction T. The first spray bar 6 has a row of first spray heads 8 arranged at a uniform spacing a along the entire length of the row. The second spray bar 7 has a row of second spray heads 9. The first spray heads 8 are fixedly positioned, for example, screwed onto the first spray bar 6. The second spray heads 9 are variably positioned on the second spray bar 7, such that each second spray head 9 is movably supported along the second spray bar 7. Non-uniform spacing a, b can be set by moving the second spray heads 9 to their respective positions.

[0018] The number of second spray heads 9 is less than the number of first spray heads 8. Figure 2 In the illustrated setup, each second spray head 9 is moved to a position aligned with the first spray head 8 along the conveying direction T, and there is a small gap a between some of the second spray heads 9, which also exists between all the first spray heads 8 and can therefore be referred to as the standard gap. Here, there is a larger gap b between the other second spray heads 9, which is at least twice the gap a. Compared to the rows of first spray heads 8, the larger gap b creates a gap L in the rows of second spray heads 9.

[0019] The page is powdered across its entire width by a first spray bar 6. Then, the page is unevenly powdered across its width by a second spray bar 7. The application of powder using the second spray bar 7 in a strip-like or zone-by-zone manner is implemented according to the printed image. For example, the gaps L may be located in areas of the printed image with little or no ink.

[0020] exist Figures 2 to 4 The diagram shows different settings for the spraying device 4, which can correspond to different printing jobs. A comparison of the accompanying drawings shows that in all settings, the first spray head 8 is in its fixed position, and the position of the gap L inside the row of the second spray head 9 varies with the setting.

[0021] Figure 5 Enlarged display Figure 4 A partial view is shown. Schematic illustration: in the first zone Z1 of the sheet (not shown), powder is applied only by the first spray head 8, and in the second zone Z2, powder is applied not only by the first spray head 8 but also by the second spray head 9. In the second zone Z2, the spray marks applied to the sheet by the two spray heads 8 and 9 overlap, whereas this overlap is not present in the first zone Z1. It should be noted that an interchangeable arrangement of the two spray bars 6 and 7 is also possible.

[0022] exist Figure 6 and 7 The diagram shows a drive unit 10, which allows each second spray head 9 to move steplessly to different distances relative to its adjacent spray heads—namely, distances a and b. The drive unit 10 includes a rail 11 that guides the second spray heads 9 in a direction orthogonal to the conveying direction T. For this purpose, a single rail 11 may also be provided.

[0023] An electric motor 12 is mounted on each second spray head 9, and this motor is connected to a pinion 13, for example, in such a way that the pinion sits on a motor shaft. The pinion 13 meshes with a rack 14, which extends parallel to the rail 11. These motors 12 are controlled in a coordinated manner by a control device (not shown). As the second spray head 9 moves along the rail 11 together with the motor 12, the pinion 13 runs along the rack 14.

[0024] Instead of the drive unit 10 shown, other drive units can be used. For example, such a drive unit may have only one common motor, which is arranged independently of the second spray head 9. This common motor can be connected to the second spray head 9 via a transmission device, which includes a switching coupling device that allows the respective second spray head 9 to be coupled to the common motor.

[0025] exist Figure 6 and 7 As shown: Each second spray head 9 has multiple spray nozzles 15, which are arranged relative to each other at a spacing a (standard spacing). An air-powder mixture for spreading the sheets is sprayed from the spray nozzles 15, just like... Figure 6As indicated by the arrow, the arrow represents the spray direction 16. In practice, the spray direction 16 corresponds to the central jet of the spray cone. The spray directions 16 of the spray nozzles 15 of the corresponding second spray head 9 are oriented parallel to each other. In the example shown, each second spray head 9 has three spray nozzles 15. However, there may be more or fewer, and in extreme cases, there may be only one spray nozzle 15. The air-powder mixture is supplied to the spray nozzles 15 through hose 17.

[0026] In the example shown, the first spray bar 6 has a first spray head 8, which may have the same structure as the second spray head 9, but unlike the second spray head, it cannot move.

[0027] In a modification not shown in the accompanying drawings, the first spray head 8 is omitted and the first spray bar 6 has a nozzle array in which the spray nozzles are arranged relative to each other at a distance a or other uniform spacing. Here, the spray nozzles can be introduced into the spray pipe, for example, as an orifice array.

[0028] List of reference numerals

[0029] 1. Printing press

[0030] 2. Paper receiver

[0031] 3. Printing facilities

[0032] 4. Spraying device

[0033] 5. Stacking

[0034] 6 First spray bar

[0035] 7 Second spray bar

[0036] 8 First spray head

[0037] 9 Second spray head

[0038] 10. Drive unit

[0039] 11 tracks

[0040] 12 motors

[0041] 13 small gears

[0042] 14. Rack and pinion

[0043] 15 Spray nozzles

[0044] 16 Spraying direction

[0045] 17 Hose

[0046] a Spacing

[0047] b Spacing

[0048] L-gap

[0049] T conveying direction

[0050] Z1 First District

[0051] Z2 Second Zone.

Claims

1. A powder spraying device for use in a printing press, comprising a first spray bar (6) and a second spray bar (7), the first and second spray bars being arranged sequentially along the sheet conveying direction (T), characterized in that, The first spray bar (6) has a row of first spray heads (8); The second spray bar (7) has a row of second spray heads (9); There is a drive device (10) for moving the second spray head (9) to a defined setting; In the defined configuration, the second spray heads (9) have different spacings (a, b) between each other within the row; In the defined setup, each second spray head (9) is moved to a position aligned with the first spray head (8) along the conveying direction (T), and there is a small gap (a) between some of the second spray heads (9), which also exists between all the first spray heads (8) and can therefore be referred to as the standard gap, wherein there is a larger gap (b) between the other second spray heads (9), which is at least twice the smaller gap (a), wherein the larger gap (b) creates a gap (L) in the row of second spray heads (9) compared to the row of first spray heads (8); and In the defined configuration, the first spray head (8) of the first spray bar (6) is aligned with the gap (L) between the first spray head (8) of the first spray bar (6) and the second spray head of the second spray bar (7) along the conveying direction (T).

2. The spraying device according to claim 1, characterized in that, The drive unit (10) is motorized.

3. The spraying device according to claim 2, characterized in that, A motor (12) is installed on each second spray head (9).

4. The spraying device according to any one of claims 1 to 3, characterized in that, The total number of second spray heads (9) of the second spray bar (7) is less than the total number of first spray heads (8) of the first spray bar (6).

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